The induction of 2'5'-oligo(A) polymerase by human interferons will be studied. The kinetics of induction will first be determined after treatment with Type I or Type II interferon. The effect of different inhibitors of protein and RNA synthesis on the kinetics of induction with the different interferons will then be studied. These experiments may establish whether interferon induces directly the synthesis of the antiviral proteins or whether this synthesis follows that of other proteins that mediate the effect of interferon. The accumulation of informational RNA in cells treated with interferon in the presence of an inhibitor of protein synthesis such as cycloheximide will be established. Once the inhibitor is removed, the cells should be capable of synthesizing the 2'5'-oligo(A) polymerase if interferon is a direct inducer of this enzyme. Another line of work will investigate the effect of cell exposure to interferon in the presence of an inhibitor of RNA synthesis. This experiment will test whether the accumulation of intracellular mediators of interferon action is a transient phenomenon or whether upon removal of the inhibitor the cells are still committed to the synthesis of the antiviral proteins.